Imaging devices, such as photoplotters and scanners, are known in the art. Scanners function by illuminating a test sample with an unmodulated optical beam and capturing the light reflected by or transmitted through the test sample after it leaves the copy. The reflected or transmitted optical signals are received by a detector and recorded. By way of example, photoplotters are used in the fields of publishing, graphic arts and the fabrication of printed circuit boards.
Internal drum photoplotters have a cylindrical surface portion to receive a media plate to be imaged. An optical beam generator emits a modulated optical feed beam onto a parabolic spinning mirror, and the mirror reflects the beam onto the media. As the mirror spins, the reflected imaging beam advances across the media surface from one side edge of the surface to an other side edge, exposing a sequence of pixels which together form a scan line generally perpendicular to the axis of the drum. The spinning mirror is mounted on a carriage, which moves along a spar oriented parallel to the axis of the drum and perpendicular to the scan line. The carriage moves continuously so that the imaging process is helical along the cylinder. The rotating imaging beam advances across the surface area of the drum in this manner until the entire image is exposed to the media.
Smaller internal drum imaging devices expose media plates having typical dimensions of 21".times.24" for "4-up" media format printing, i.e., large enough to fit four images on a plate, and plates of 32".times.42" for plates of "8-up" format printing. The widths of the smaller plates permit the radius of the internal drum to be sufficiently small and yet provide access between the drum and the spar for loading and unloading the media plates onto and off of the drum.
The dimensions of larger media plates for larger imaging devices capable of exposing media of larger format printing, e.g., "16-up", are approximately 52" by 68". The handling and loading of the larger media onto the internal drum typically requires the assistance of one or more individuals.
In one other machine, the loading and unloading of media plates is performed automatically. Such a machine is shown and described in the above-noted U.S. Pat. Application entitled "Media Feed Apparatus For An Imaging Device". Each media plate is moved along a transport path oriented perpendicular to the drum axis. The media feed apparatus is employed with large format media, e.g., 16-up, and accordingly requires a relatively large footprint. Such apparatus require substantial time to load and unload the media plates. Since there is no separate mechanism for removing any interleaves, the same suction cups used to move the media plates would also remove the interleaf. Moreover, the media feed apparatus is very complicated and correspondingly expensive.
Accordingly, it is an object of the present invention to provide an automated apparatus for loading media plates into and unloading media from an imaging device that reduces the cycle time required to load and remove media plates of media onto and from an internal drum of the imaging device.
It is another object to provide an automated media feed apparatus which automatically adapts to the use of different-sized media, and does not require manual reconfiguration of the apparatus.
It is a further object to provide an automated media feed apparatus for an imaging device that accurately loads a media plate onto the internal drum of the imaging device, and compensates for skewing of the media plate which may occur during loading.
It is still another object to provide an automated media feed apparatus for an imaging device unloads a media plate from the internal drum of the imaging device, and accurately positions the imaged media plate on a conveyor for transferring the imaged plate for further processing.
It is yet another object to provide a conveyor capable of transferring the imaged plates in one of several available apparatus for further processing of the imaged media plates.